Goals for coming year: 1. Transcription termination. a. We will do a fine-structure analysis of the rho gene isolating new chain-terminating mutations and deletions. One goal of the project is to determine whether rho is essential for cell growth. We will also isolate and characterize new mutants alleles of the genes for RNA polymerase which restore transcription termination in the presence of defective rho alleles. b. We have initiated a collaboration with Dr. Terry Platt of Yale University who is doing the DNA sequence of our ttrp mutants. The results will help define the ttrp site and to suggest, for instance, whether we should continue our search for ttrp mutants. 2. Stable RNA control. We have initiated a collaboration with Dr. Art Landy of Brown University who is doing the RNA sequence of tyrT promoter mutations. The first of these has been determined and is a single base change in the "Pribnow Box" of the tyrT promoter. The isolation and sequencing of such mutants will be continued. In addition, we will seek mutants in genetically unlinked loci which alter the expression of the tyrT gene. Analysis of such mutants should reveal new information on the regulation of stable RNA synthesis.